Two Types of Liquid Phase Separation Induced by Soft Centrifugation in Aqueous Ethyl Acetate Using Ethanol as Cosolvent

Coelfen, Helmut and Rosenberg, Rose and Haffke, Dirk and Stemplinger, Simon and Zemb, Thomas and Horinek, Dominik (2023) Two Types of Liquid Phase Separation Induced by Soft Centrifugation in Aqueous Ethyl Acetate Using Ethanol as Cosolvent. RESEARCH, 6: 0026. ISSN 2096-5168, 2639-5274

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Abstract

Water/ethyl acetate/ethanol is widely used as a "green" extractant system. We show that 2 different types of phase separation can be induced upon centrifugation in this ternary system using ethanol as a cosolvent of water and ethyl acetate: centrifuge-induced criticality and centrifuge-induced emulsification. The expected composition profiles of samples after centrifugation can be represented by bent lines in a ternary phase diagram when gravitational energy is added to the free energy of mixing. The experimental equilibrium composition profiles behave qualitatively as expected and can be predicted using a phenomenological theory of mixing. The concentration gradients are small except near the critical point, as expected for small molecules. Nevertheless, they are usable when accompanied by temperature cycles. These findings open new possibilities of centrifugal separation, even if control is delicate during temperature cycles. These schemes are accessible even at relatively low centrifugation speed for molecules that float and sediment with apparent molar masses several hundred times larger than the molecular mass.

Item Type: Article
Uncontrolled Keywords: MULTIWAVELENGTH DETECTOR; ORGANIC-COMPOUNDS; DISPERSIONS; SCATTERING; MIXTURES; WATER;
Subjects: 500 Science > 540 Chemistry & allied sciences
Divisions: Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Chemistry VI - Physical Chemistry (Solution Chemistry) > Prof. Dr. Dominik Horinek
Depositing User: Dr. Gernot Deinzer
Date Deposited: 11 Mar 2024 15:24
Last Modified: 11 Mar 2024 15:24
URI: https://pred.uni-regensburg.de/id/eprint/59683

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